Image Resizing Maintaining Height/Width Ratio

My name is Emanuele Briano, I am 23 years old. I'm an Industrial and Management Engineer from Italy.
I have expertize in: optimization of complex systems, production flow optimization, linear programming, statistical methods, simulation, design of experiments, business management.
I also operate in web consulting and web design. I realise professional web pages, static or dynamic (usually in ASP.NET), from a design based on usability to realisation and online marketing.
My Web Site (english) is http://www.emanuelebriano.it/e_default.aspx
My Web Site (Italian) is http://www.emanuelebriano.it